A study of EEG, electroretinogram, visual evoked potential, and eye movements in classical lissencephaly.

EEG, flash electroretinogram (ERG), and visual evoked potential (VEP) findings are described in eight children with classical lissencephaly (six girls, two boys), with a mean age of 17.6 months (range 2 to 60 months). The EEG shows typically high-voltage activity. Eye movements were formally recorded in two patients, and both showed features associated with oculomotor apraxia. The ERG and VEP to flash stimulation were normal in all cases. Two subjects had pattern reversal stimulation, and their pattern VEPs were within normal limits. Some patients with lissencephaly may appear to have delayed visual maturation on first presentation, and EEG and eye movement studies are valuable in indicating neurological deficiency at an early stage in these subjects.